1. Technical Field
The present invention relates to an oscillator, an electronic apparatus, and a moving object.
2. Related Art
An angular velocity sensor and an acceleration sensor using an oscillator have been used in a technology for autonomically controlling the attitude of a ship, an airplane, a rocket, and other moving objects. In recent years, the sensors are also used in vehicle body control in a vehicle, car position detection in a car navigation system, vibration controlled correction in a digital camera, a video camcorder, a mobile phone (what is called hand-shake correction), and other types of operation. As the performance of moving objects and electronic apparatus advances, improvement in sensitivity of the sensors is required. For example, there has been a known a rotational speed sensor in which two oscillating units are movably suspended over a basic device and allowed to incline around a suspension piece, as described in FIG. 4 in JP-T-2008-514968. In the rotational speed sensor, a reader formed of the oscillating units and electrodes reads a capacitance change that occurs when the oscillating units are inclined around the suspension piece in response to a rotational speed applied to the oscillating units and determines the rotational speed.
The rotational speed sensor described in JP-T-2008-514968 has an exterior made of a material primarily containing silicon or any other element and formed, for example, by using a photolithography method and an etching method. When the shapes of the two displacement portions (oscillating units) differ from each other due, for example, to manufacturing errors at the time of exterior formation, the natural oscillation frequencies of the displacement portions undesirably differ from each other. When angular velocity or acceleration is applied to the oscillating units in this state, the angular velocity or acceleration could be detected with lowered precision because the amounts of displacement of the two displacement portions differ from each other and hence electrostatic capacitance created between one of the displacement portions and a fixed electrode differs from electrostatic capacitance created between the other displacement portion and the fixed electrode.